Kinda depends on what features in sync made you like it.

Overall, boost, connect, thunder and summit each get close to parity, but only close. But, you could say that in reverse, (that sync only gets close to parity with any of them) it isn’t a slight against any of them.

Eternity is another one that I’ve had good use of, but development on that seems to be stopped as well, so I dunno if that’s a useful option.

Past those, you get less similarity in ux and ui than would make sense to compare. Like, the apps that mimic voyager (or whatever the popular iOS reddit app was called), things are laid out so different that if you used sync as a primary, you aren’t likely to enjoy that ui.

On a phone, I kinda favor connect over sync, despite it looking very unlike it compared to boost or eternity. But on a tablet, nothing else does double columns in portrait worth a damn for me, and aren’t great in landscape either. But boost and eternity come the closest to the visual ease sync has.